3-Bromobenzoic acid → 1-Bromo-3-tert-butylbenzene

Temperature

145 °C

A suspension of 4.02 g (20 mmol) of m-bromobenzoic acid (Compound 23) in 10 ml hexane was cooled in an ice-bath under nitrogen and then treated slowly with 40 ml of 2M (80 mmol) trimethylaluminum in hexane. The hexane was removed by distillation under nitrogen and the apparatus modified for reflux. The reaction mixture was then heated in an oil bath at 140-150 degrees C. for 3 hours. The oil bath was then replaced by an ice-water bath and the reaction mixture was quenched by the slow dropwise addition of water. The mixture was acidified with dilute HCl and mixture heated at reflux until the aluminum salts were dissolved. The reaction mixture was allowed to cool and extracted with 3×8 ml ether. The ether extracts were combined, washed with dil. HCl, water and saturated NaCl and then dried (MgSO4). The solvent was removed in-vacuo and the residue distilled to give a mixture of the title compound and 3-(1-methyl-ethenyl)bromobenzene as a colorless oil. A small portion (200 mg) of this mixture was dissolved in 1 ml of methylene chloride and then treated with a solution of 200 mg of m-chloroperbenzoic acid in 4 ml of methylene chloride. The mixture was stirred at room temperature for 1 hour and the methylene chloride removed in-vacuo. The residue was dissolved in hexane and filtered through a short silica column and the filtrate concentrated in-vacuo to give pure title compound as a colorless oil. PMR (CDCl3): & 1.30 (9H, s), 7.25 (1H, m), 7.41 (2H, m), 7.65 (H, t, J~2.1 Hz).

1. temperaturewas cooled in an ice-bath under nitrogen
2. customThe hexane was removed by distillation under nitrogen
3. temperaturefor reflux
4. customThe oil bath was then replaced by an ice-water bath
5. customthe reaction mixture was quenched by the slow dropwise addition of water
6. temperatureheated
7. temperatureat reflux until the aluminum salts
8. dissolutionwere dissolved
9. temperatureto cool
10. extractionextracted with 3×8 ml ether
11. washwashed with dil. HCl, water and saturated NaCl
12. dry with materialdried (MgSO4)
13. customThe solvent was removed in-vacuo
14. distillationthe residue distilled
15. customto give

ORD record

ord-5bcc7d5cc2ca4c2e8b76d2f69535a2f7

Source dataset

uspto-grants-1995_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05414007